"The explosion comes amid a sharp increase in explosions at industrial sites, key gas pipelines and Revolutionary Guard bases in Iran in recent years, which some here attribute to sabotage by the United States." - Washingtom Post// And Iran Independent News Service attributes the blast to a fire in the base, not far from the ammunition dump. Looking at the larger picture, I allow myself to be skeptical of the official explanation which might be intended to "explain" why the Guard's base could be penetrated despite previous incidents. An alternative possibility is that this is the work of Mossad. Shihab missiles are a worry to Israel and the US. But the CIA is inept in using human agents, so I give preference to Mossad. It is difficult to believe the internal militant opposition Jundollah is responsible because they are Baluchis, residing far from Tehran in the southeast corner of Iran. In any case, good job by whoever is responsible.
Saudi FM: We hope Iran uses sanction relief for development, not nefarious activities (Reuters)
from the article: Iran exile group: Explosion of rockets caused deadly blast near Tehran